Note that the curves are examples and cannot be used for
readings.
IEC trip curves
0.0
1
5
10
10
50
100
100
500
1000
1000
5000
10000
2
3
4
1
A
170
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
2.25
X
Y
TM072668
Pos.
Description
Y
Time [s]
X
x I
rated
A
Class "p"
1
Class 30
1
Class 20
3
Class 10
4
Class 5
Example:
1.
Set the IEC trip class to class 20.
2.
Set the overload limit to 10 A. The rated motor current is stated
on the nameplate.
At a motor current of 22.5 A (10 x 2.25), a pump is to cut out after
approx. 170 seconds. In addition to IEC trip curves, a fixed 4 x
I
rated
in 2 seconds is implemented to protect especially small motors
from overheating (see grey area on drawing).
Contactor Current Protection (CCP)
In addition to the IEC trip class, a Contactor Current Protection
(CCP) trip class is implemented to protect the internal contactors in
the product from overheating.
10000
1000
100
10
1
0.1
10
20
30
40
50
60
70
80
Y
5
4
3
2
6
X
1
TM072272
Pos.
Description
Y
Trip time [s]
X
Current [A]
1
CCP
2
Class 30
Pos.
Description
3
Class 20
4
Class 10
5
Class 5
6
CCP + Class 20
Full-load current is set to 10 [A] and trip class 20 is selected.
•
Motor overload. When the motor is overloaded with 15 [A], it
will take ~800 seconds to trip the motor protection when trip
class 20 is selected.
•
The pump is blocked. If the pump is blocked and the motor has
a locked-rotor current specified to 65 [A], it will take
approximately 1 second to trip the motor protection due to the
contactor-current protection.
The contactor is worn out
LC 231 has a wear-out counter for the contactor(s) which are based
on the actual current when the motor is switched off by the
protection function.
When 90 % of the estimated wear-out for the contactor is reached,
the warning code 220 appears on the operating panel. In Grundfos
GO Remote, the warning
Contactor wear out
appears.
When 100 % of the estimated wear-out for the contactor is reached,
the alarm code 220
Contactor wear out
appears on the operating
panel and the controller will not be able to start the pumps.
The pump is blocked
To prevent that the contactor gets worn out too fast if the pump is
blocked, a maximum number of restarts are allowed by the
controller.
Maximum number of blocked motor restart
can be set
from 1 to 3 via Grundfos GO Remote. Tripped by the CCP-curve.
The alarm code 51 appears on the operating panel. In Grundfos GO
Remote, the alarm
Blocked
appears.
If the motor has reached the maximum numbers of restarts, 1 to 3
times, due to a blocked motor, it is possible to reset the failure up to
3 times manually. After that LC 231 will wait 24 hours before trying
to restart the motor again. Alternatively, switch off the main power
supply to LC 231 for a minimum of 30 seconds to clear the alarms.
A blockage alarm is typically triggered when the motor starts and in-
rush current trips the motor. The maximum allowed blockage
situations are limited to 6 times during a 24-hour period. If
the
Maximum number of blocked motor restart
is set to 3, the
control unit tries to restart the motor 3 times before a manual reset
is needed. If it occurs 3 times again after the reset, the control unit
has reached the maximum number of blockages.
Related information
6.17.4 Setting the motor protection with Grundfos GO Remote
6.18 Alarm reset
6.18.1 Resetting alarms and warnings manually with Grundfos
GO Remote
1.
Go to
Alarms and warnings
.
2.
Press
Reset alarm
.
All current alarms and warnings have been reset. However, if
the fault causing the alarm or warning has not been removed,
the alarm or warning will appear again.
3.
If you want to delete all alarms and warnings from the history
log, press
Show log
>
Reset alarm and warning logs
.
6.18.2 Setting the automatic alarm reset with Grundfos GO
Remote
1.
Go to
Settings
>
Automatic alarm reset
.
18
English (GB)
Summary of Contents for LC 231
Page 2: ......
